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Mankato Researchers Study Road Salt Use

MANKATO, Minn. (AP) — Roads across Minnesota remained icy Monday after last week’s storm, which was nasty by most people’s standards. But road salt researchers at Minnesota State University in Mankato couldn’t have been happier.

Civil engineering professor Steve Druschel and two of his students gathered beneath the North Star Bridge as the snow fell Thursday to collect samples of murky road melt from the highway above.

“This is a perfect storm for our tests,” Druschel told The Free Press. He’s leading research on how and when the Minnesota Department of Transportation should apply anti-icing solutions and salt on roads to most effectively remove snow and produce the safest conditions for motorists.

Finding the most cost-effective way to use chemicals is increasingly important, he said. Rock salt, delivered in the summer, sells for about $80 a ton, but that has spiked to as much as $250 in some places because of shortages. Highway crews also use magnesium chloride, a greenish solution they spray on pavements prior to storms.

“The liquid is good and it helps. But it can cost up to twice as much and you’re not getting double the melting for the price,” Druschel said.

Danielle Alinea, a junior who wants to work in wastewater management, said participating in the research has helped her studies.

“I’m getting a good perspective of designing an experiment and how much work it takes,” she said.

The team is also studying how different types of traffic affect ice and snow.

“One thing we’re seeing is that the big trucks squeeze a lot of water out of the snow,” Druschel said.

Druschel’s team placed large plastic barrels under the North Star Bridge, which carries Highway 169 over the Minnesota River. Drains from the roadway funneled the runoff into the barrels for analysis of salt content. The team also set up time-lapse cameras to record the amount and type of vehicles using the bridge. They will use that information along with weather and MnDOT records to analyze what worked best.

“It’s been a great winter to test things. We have so much data. We just want to collect as much as we can and we’ll sort it out in the spring,” Druschel said.